Human hearing is perhaps not comparable to certain other members of the fauna of our planet. However, within our species and for routine interaction with the world around us, our hearing is as adequate as can be. We can normally hear frequencies of sound between 20 Hz and 20 kHz. However, this range of hearing ability deteriorates with age, exposure to sounds during one’s lifetime and a variety of other factors. The biological ear is not as immortal as the sounds that resonate through it. The functioning of the ear is like a sophisticated receiver sending the vibrations from across the air to the brain. The ear functions much like a relayed computer in carrying the sound to the brain. The outer ear which we see outside collects and concentrates the sound waves sent to it. This then gets transferred to the middle ear which processes the different noises and translates them over to the Inner ear. The Inner ear is a fluid filled chamber, also known as the Cochlea, where these sound messages are translated from waves in the fluid, into nerve impulses, which are then received by the brain. The brain, thanks to a sophisticated network of auditory nerves, receives this information which it then interprets into coherent sounds. So, we either scream in agony over loud music or smile with content at the sweetest melody.
But, what about people with extremely limited or no hearing ability ? Technology has the answer in the form of what is known as the Cochlear implant. It is usually recommended only for people for whom other forms of therapy to restore or improve hearing is unfruitful. While the conventional hearing aid amplifies the sound received by it into the ear, the cochlear implant directly stimulates the auditory nerves of the cochlea. This electronic device is surgically inserted into the skin just behind the person’s ear. Externally, the device consists of a microphone that picks up sound from the environment which is then filtered by a sound processor to cancel out non-essential noises that are not required before sending to a magnetic pad transmitter placed behind the external ear. A receiver and a stimulator surgically placed inside the person’s bone just beneath the skin, converts the sound signals sent to it by electromagnetic induction into electrical signals which are relayed to extensive array of electrodes (16-24 electrodes in a regular model) wound around the cochlea of the natural ear. The electrodes are programmed to strobe on and off to mimic the activities of the auditory nerves, thus sending this information directly to the brain. The patient trains himself/herself over time to decipher the noise as coherent human speech.
Article comments
1 - wildnfree
Quite an interesting article, it will be interesting to see what kind of feed back it receives.
Thank you,
2 - Christopher Rose
Great and fascinating stuff, V.R., thanks for writing this.